The present invention relates to a bracing system for bracing a marine caisson (conductor pipe) emanating from a water bottom and extending above the water level of a body of water, as well as a method of installation therefore. The system of the present invention allows the installation of a bracing structure without the necessity of a heavy lift boat, the present system utilizing a tugger or winch temporarily affixed preferably to the upper portion of the riser, or alternatively placed upon a nearby vessel such as a jack-up rig, or the barge upon which the brace is transported to the installation site.
In the preferred embodiment of the present invention, a bracing structure is provided in the form of an elongated bracing member having first and second ends, the first end having a pile sleeve for engaging the bottom, the second end having a doubler plate or the like for engaging the caisson above the water line. A pulley is provided on the caisson above the water line, in the vicinity of (preferably above) where the doubler plate is to be mounted on the caisson. A cable having first and second ends is provided, the first end affixed to the bracing member in the vicinity of the doubler plate, the second end engaging the tugger or winch, the cable passing through a first pulley in the vicinity of the installation area to guide the first end of the brace to the caisson. The present invention is illustrated as a single leg brace, but it is noted that two, three, or more legs are generally utilized to brace the conductor pipe in the manner illustrated in the present application.
In use, the tugger draws the cable so as to urge the doubler plate to the caisson above the water line in the vicinity of the installation area. A small crane may be utilized to urge the bracing into the water from the barge, without having to fully lift same, the small crane only partially supporting the bracing, so as to dispense with the necessity of a larger crane, and requisite larger vessel.
While the prior art anticipates many and diverse minimal platform installation systems, none are believed to contemplate a system of installation with the ease and economy of the present invention.
U.S. Pat. No. 5,308,194 to Carruba issued 1994 teaches an xe2x80x9cOffshore Support Structure Apparatusxe2x80x9d wherein there are provided first and second, diagonal braces having first and second ends, the first, lower ends including pile sleeves to receive piles at the water bottom, the second, upper ends including a doubler plate configured to engage guide plates fixed to the Caisson, so that the doubler plate come in abutting relationship with the Caisson. See FIGS. 12-15.
U.S. Pat. 5,026,210 issued 1991 to Carruba teaches an xe2x80x9cOffshore Support Structure Method and Apparatusxe2x80x9d wherein a pivot support member is provided at the upper portion of the caisson to engage the upper portion of each brace at or above the waterline to aid in the installation of the brace.
U.S. Pat. No. 5,181,799 issued 1993 to Carruba is related to the above ""210 patent, likewise teaching a support structure supported by only two legs having pile skirts spaced by a bracing member, the upper portions of the pile skirts connecting to the conductor pipe such that the bracing legs are xe2x80x9csecured at their upper ends to the conductor pipe and the lower ends of the legs can be moved downwardly into contact with the groundxe2x80x9d.
U.S. Pat. No. 4000624 teaches a system whereby the conductor pipe is supported by bracing legs pivotally attached thereto under the waterline.
U.S. Pat. No. 4,818,145 to Carruba is the parent to the above Carruba patents ""210 and ""799, teaching a system employing a pivoting brace concept for installation.
British Patent 1,1 56,651 issued 1961 illustrates a xe2x80x9cmarine structurexe2x80x9d utilizing first and second, pivotally attached braces to support same.
Thus, while the prior art teaches several systems having concepts incorporating bracing systems or the like for bracing a conductor pipe, caisson, or the like, none would appear to teach, suggest, or otherwise contemplate the system of the present invention.
The present invention provides a marine caisson bracing system which is more efficient to install, requires less heavy lifting equipment, and less personnel than the prior art.
Unlike the prior art cited above, the present invention allows the installation of a bracing structure without the necessity of a heavy lift boat, instead incorporating a tugger or winch temporarily affixed to the upper portion (or top) of the caisson. Alternatively, the winch could be situated removed from the caisson, via a cable pulley or the like situated in the upper section of the caisson .
A bracing structure is provided in the form of an elongated bracing member having first and second ends, the first end having a pile sleeve for engaging the bottom, the second end having a doubler plate or the like for engaging the caisson above the water line. A cable pulley is provided on the caisson above the water line, in the vicinity of where the doubler plate is to be mounted on the caisson. A cable having first and second ends is provided, the first end affixed to the bracing member in the vicinity of the doubler plate, cable passing through a first pulley situated on the caisson in the vicinity of the installation area, the second end engaging the tugger or winch.
In use, the tugger draws the cable so as to urge the doubler plate to the caisson above the water line in the vicinity of the installation area via the first pulley. A small crane may be utilized to urge the bracing into the water from the barge, without having to fully lift same, the small crane only partially supporting the bracing, so as to dispense with the necessity of a larger crane, and requisite larger vessel.
It is therefore an object of the present invention to provide a marine caisson bracing system and method for installation therefore which requires less heavy lifting apparatus than that contemplated by the prior art.
It is another object of the present invention to provide a system for bracing a marine caisson for the formation of a minimal platform utilizing a cable positioning method, which cable is guided by a first pulley mounted to the caisson and situated in the vicinity of the brace/caisson connection, and a second pulley or winch mounted to the caisson and situated above said first pulley.
It is another object of the present invention to provide a bracing system comprising a brace member having first and second ends, the first end including a pile sleeve configured to contact a water bottom, and a second end having a doubler plate configured to engage the caisson above the water line, the second end of the brace member further configured to engage a cable, said cable passing through said first pulley and second pulley, or winch, so as to facilitate the positioning of said second end of said brace adjacent to said caisson to support and reinforce same.
Lastly, it is an object of the present invention to provide a method and system for bracing and reinforcing a caisson via brace member, said brace member configured for positioning adjacent to a caisson for supporting a minimal platform utilizing a cable/pulley and winch system.